Long term evolution (“LTE”) of the Third Generation Partnership Project (“3GPP”), also referred to as 3GPP LTE, refers to research and development involving the 3GPP LTE Release 8 and beyond, which is the name generally used to describe an ongoing effort across the industry aimed at identifying technologies and capabilities that can improve systems such as the universal mobile telecommunication system (“UMTS”). The notation “LTE” is also used to refer to communication systems and components designed under 3GPP LTE standards. The notation “LTE-A” is generally used in the industry to refer to further advancements in LTE. The goals of this broadly based project include improving communication efficiency, lowering costs, improving services, making use of new spectrum opportunities, and achieving better integration with other open standards.
The evolved universal terrestrial radio access network (“E-UTRAN”) in 3GPP includes base stations providing user plane (including packet data convergence protocol/radio link control/media access control/physical (“PDCP/RLC/MAC/PHY”) sublayers) and control plane (including a radio resource control (“RRC”) sublayer) protocol terminations towards wireless communication devices such as cellular telephones. A wireless communication device or terminal is generally known as user equipment (also referred to as “UE”). A base station is an entity of a communication network often referred to as a Node B or an NB. Particularly in the E-UTRAN, an “evolved” base station is referred to as an eNodeB or an eNB. For details about the overall architecture of the E-UTRAN, see 3GPP Technical Specification (“TS”) 36.300 v8.7.0 (2008-12), which is incorporated herein by reference. For details of the communication or radio resource control management, see 3GPP TS 25.331 v.9.1.0 (2009-12) and 3GPP TS 36.331 v.9.1.0 (2009-12), which are incorporated herein by reference.
As wireless radio communication systems such as cellular telephone, satellite, and microwave communication systems become widely deployed and continue to attract a growing number of users, there is a pressing need to accommodate efficiently a large and variable number of communication devices that transmit an increasing quantity of data within a fixed spectral allocation and limited transmitter power levels. The increased quantity of data or traffic is a consequence of wireless communication devices transmitting video information and surfing the Internet, performing ordinary voice communications, and enabling communication among local processing devices such as personal computers and routers. Such processes are generally performed while accommodating substantially simultaneous operation of a large number of wireless communication devices.
The current development of the communication networks, therefore, is enabling the use of larger bandwidths for the associated communication systems. The larger bandwidth usage typically requires new rules and conventions for the spectrum handling. Thus, the communication system allocates spectrum based on the amount of traffic. Typically, if there is a reasonable amount of traffic, then the communication system allocates a primary communication channel. Occasionally, when the traffic load increases, the communication system may need to use larger amount of spectrum referred to as a secondary communication channel.
Local area networks (“LANs”) designed under 3GPP LTE specifications can complement existing cellular communication systems (or networks) and standards such as global system for mobile communications (“GSM”) networks, UMTS and high speed packet access (“HSPA”) networks. The local area networks are targeted for inclusion in 3GPP LTE Release 12 of the technical specifications. Unlike a cellular communication network, a local area network can utilize the license-exempt spectrum to take advantage of the additional available bandwidth. Bands reserved for time division duplex (“TDD”) operation are also candidates for local area networks with larger bandwidth.
Currently, wireless local area networks such as wireless fidelity (“Wi-Fi™”) communication networks based on the Institute of Electronic and Electrical Engineers (“IEEE”) family of Technical Standards 802.11 are targeted to operate on the 2.4 to 5 gigahertz (“GHz”) license-exempt bands where LTE wireless communication networks may plan to operate. The IEEE family of Technical Standards 802.11 that describes local area networks has evolved over the past twenty years. The latest developments in throughput enhancements have resulted in Wi-Fi™ certification of wireless communication devices (or other communication system devices) under the recent IEEE Technical Standard 802.11n. The devices certified under IEEE Technical Standard 802.11n may utilize 2×20 megahertz (“MHz”) transmission bandwidth.
A follow-on effort to improve throughput of wireless communication devices operating under the IEEE family of Technical Standards 802.11 is IEEE Technical Standard 802.11ac. Technical Standard 802.11ac is directed at operation of a wireless local area network (“WLAN”) communication device that is capable of using 8×20 MHz=160 MHz channel bandwidth and classifies the applied operational communication channels into primary communication channels employing primary spectrum usage (e.g., communication channel used to allocate transmission opportunities (“TXOPs”)) and secondary communication channels (e.g., communication channels that enable data transmission with larger bandwidth). A primary communication channel can be used to obtain communication resources (e.g., do random access to obtain transmission opportunities (“TXOPs”)), whereas a secondary communication channel carry traffic during the transmission opportunities if the communication channels have been idle at least for a priority interframe spacing (“PIFS”) before initiation of the transmission opportunities.
LTE-based communication systems or networks (which are also generally cellular communication systems that operate with scheduled communication resources) and Wi-Fi-type communication systems or networks (which are decentralized with, for instance, contention-based carrier sensing multiple access (“CSMA”)) can create harmful mutual interference. Both communication system or network types generally do not operate well if deployed on the same communication channel, and interference between such communication systems or networks becomes an issue when such communication systems or networks share spectrum in a common physical area. Mixed communication system operation, however, can provide high levels of communication performance due to spectrum sharing by user equipment between coexisting cellular and local area network communication modes. Enhancements are thus needed for an LTE-based communication system or network to improve its reliability and operation in the presence of a local area network such as a Wi-Fi communication network operating partially or completely on the same communication channel.
Coexistence of a communication system with scheduled communication resources and a communication system employing contention-based communication resources has been an ongoing and challenging problem because such communication systems operate with different communication resource allocation processes. Such communication systems are not likely to be capable of exchanging signaling between each other in the near future.
To achieve better network throughput, future communication systems or networks that employ scheduled communication resources will need to coexist and operate efficiently in an environment with communication systems or networks that employ contention-based communication resources. Interference between such communication systems or networks should be resolved to provide reliable and efficient operation of each communication system or network type. Thus, there is need for an improved system and method that can addresses interference issues for wireless communication devices that may coexist in primary and secondary channels that avoid the deficiencies of present communication systems.